Controllability improvement of zero-power magnetically levitated system by dither

Author

Tomono, Hirotaka ; Kiwaki, Hisakatsu

Author_Institution

Dept. of Electr. Eng., Kyushu Sangyo Univ., Fukuoka, Japan

Volume

1

fYear

1998

fDate

17-22 May 1998

Firstpage

588

Abstract

A zero-power magnetically levitated (MAGLEV) system using a permanent-electro hybrid magnet has a defect of current fluctuation due to nonlinearity of the intermittent domain of a PWM-controlled current controller which may cause unfavorable vibration to the levitated object. To improve controllability, application of dither to the current controller is studied. Transfer characteristics of the current controller applied by dither have a tendency to show better linearity but lower gain. Measured and analysis results by the describing function method agree very well. A current controller with 11 kHz PWM carrier and 500 Hz dither frequency shows very little current fluctuation without current feedback. As a result, a MAGLEV model using the current controller realizes very quiet levitation without vibration

Keywords

PWM power convertors; bridge circuits; controllability; describing functions; electric current control; electromagnets; magnetic levitation; transportation; 11 kHz; 500 Hz; MAGLEV model; PWM-controlled current controller; controllability improvement; current fluctuation defect; describing function method; dither; permanent-electro hybrid magnet; transfer characteristics; zero-power magnetically levitated system; Control systems; Controllability; Fluctuations; Frequency; Linearity; Magnetic domains; Magnetic levitation; Nonlinear control systems; Pulse width modulation; Vibration control;

fLanguage

English

Publisher

ieee

Conference_Titel

Power Electronics Specialists Conference, 1998. PESC 98 Record. 29th Annual IEEE

Conference_Location

Fukuoka

ISSN

0275-9306

Print_ISBN

0-7803-4489-8

Type

conf

DOI

10.1109/PESC.1998.701958

Filename

701958